1. Field of the Invention
This invention relates in general to decalcomania and in particular to an improved decalcomania which carries a water soluble coating which allows an operator to observe when the optimum time for making the transfer of the decalcomania occurs.
2. Description of the Prior Art
Japanese patent application No. 1966--85154 (Patent Publication No. 1970--32643) assigned to the assignee of the present invention discloses decalcomania arrangements.
In the prior art, it has been necessary for the supporting structure for the decalcomania to be immersed into a quantity of a special solution consisting of water and specific organic solvent when it is desired to apply or transfer a decalcomania such as a marking comprising printed figures, patterns or letters to an object and the decalcomania is to be transferred from the supporting structure. An adhesive of the so-called solvent activated typed have been used to attach the decalcomania to the supporting structure.
The preparation of the special solution is costly and requires intricate labor and thus has substantially increased the cost of transferring decalcomanias.
Another inconvenience of the prior art is that the user often has had to rely upon imported specific organic solvents for the preparation of the special solution and consequently such solutions are often not readily available and are costly.
With the supporting structure of the prior art, the transfer of the decalcomania operation has largely depended on the length of time during which the supporting structure is maintained immersed in the special solution and, for example, transfer or application of the decalcomania is almost impossible when the time of immersion is relatively short since a coat of water soluble separating agent will not be sufficiently dissolved and the layer of adhesive will not be sufficiently activated. At the same time, longer times of immersions have resulted in the danger that the layers of the printed ink adhesive and the other substances might flow out into the special solution.
Thus, the time during which the supporting structure is left immersed in the special solution is an important factor in transfer or application of decalcomania from the supporting structure to the object and this time of immersion must be set depending upon the temperature of the special solution so that good results of transfer operation have been achieved only by the user who is sufficiently experienced and skillful in such operations.